1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
|
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2011 Gary Mills
*
* Copyright (c) 1999,2000 by Sun Microsystems, Inc.
* All rights reserved.
*/
/*
* fsck_pcfs -- routines for manipulating the BPB (BIOS parameter block)
* of the file system.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libintl.h>
#include <sys/types.h>
#include <sys/dktp/fdisk.h>
#include <sys/fs/pc_fs.h>
#include <sys/fs/pc_dir.h>
#include <sys/fs/pc_label.h>
#include "pcfs_common.h"
#include "fsck_pcfs.h"
#include "pcfs_bpb.h"
extern off64_t FirstClusterOffset;
extern off64_t PartitionOffset;
extern int32_t BytesPerCluster;
extern int32_t TotalClusters;
extern int32_t LastCluster;
extern int32_t RootDirSize;
extern int32_t FATSize;
extern short FATEntrySize;
extern bpb_t TheBIOSParameterBlock;
extern int IsFAT32;
extern int Verbose;
static void
computeFileAreaSize(void)
{
int32_t dataSectors;
int32_t overhead;
/*
* Compute bytes/cluster for later reference
*/
BytesPerCluster = TheBIOSParameterBlock.bpb.sectors_per_cluster *
TheBIOSParameterBlock.bpb.bytes_per_sector;
/*
* First we'll find total number of sectors in the file area...
*/
if (TheBIOSParameterBlock.bpb.sectors_in_volume > 0)
dataSectors = TheBIOSParameterBlock.bpb.sectors_in_volume;
else
dataSectors =
TheBIOSParameterBlock.bpb.sectors_in_logical_volume;
overhead = TheBIOSParameterBlock.bpb.resv_sectors;
RootDirSize = TheBIOSParameterBlock.bpb.num_root_entries *
sizeof (struct pcdir);
overhead += RootDirSize / TheBIOSParameterBlock.bpb.bytes_per_sector;
if (TheBIOSParameterBlock.bpb.sectors_per_fat) {
/*
* Good old FAT12 or FAT16
*/
overhead += TheBIOSParameterBlock.bpb.num_fats *
TheBIOSParameterBlock.bpb.sectors_per_fat;
/*
* Compute this for later - when we actually pull in a copy
* of the FAT
*/
FATSize = TheBIOSParameterBlock.bpb.sectors_per_fat *
TheBIOSParameterBlock.bpb.bytes_per_sector;
} else {
/*
* FAT32
* I'm unsure if this is always going to work. At one
* point during the creation of this program and mkfs_pcfs
* it seemed that Windows had created an fs where it had
* rounded big_sectors_per_fat up to a cluster boundary.
* Later, though, I encountered a problem where I wasn't
* finding the root directory because I was looking in the
* wrong place by doing that same roundup. So, for now,
* I'm backing off on the cluster boundary thing and just
* believing what I am told.
*/
overhead += TheBIOSParameterBlock.bpb.num_fats *
TheBIOSParameterBlock.bpb32.big_sectors_per_fat;
/*
* Compute this for later - when we actually pull in a copy
* of the FAT
*/
FATSize = TheBIOSParameterBlock.bpb32.big_sectors_per_fat *
TheBIOSParameterBlock.bpb.bytes_per_sector;
}
/*
* Now change sectors to clusters. The computed value for
* TotalClusters is persistent for the remainder of execution.
*/
dataSectors -= overhead;
TotalClusters = dataSectors /
TheBIOSParameterBlock.bpb.sectors_per_cluster;
/*
* Also need to compute last cluster and offset of the first cluster
*/
LastCluster = TotalClusters + FIRST_CLUSTER;
FirstClusterOffset = overhead *
TheBIOSParameterBlock.bpb.bytes_per_sector;
FirstClusterOffset += PartitionOffset;
/*
* XXX this should probably be more sophisticated
*/
if (IsFAT32)
FATEntrySize = 32;
else {
if (TotalClusters <= DOS_F12MAXC)
FATEntrySize = 12;
else
FATEntrySize = 16;
}
if (Verbose) {
(void) fprintf(stderr,
gettext("Disk has a file area of %d "
"allocation units,\neach with %d sectors = %llu "
"bytes.\n"), TotalClusters,
TheBIOSParameterBlock.bpb.sectors_per_cluster,
(uint64_t)TotalClusters *
TheBIOSParameterBlock.bpb.sectors_per_cluster *
TheBIOSParameterBlock.bpb.bytes_per_sector);
(void) fprintf(stderr,
gettext("File system overhead of %d sectors.\n"), overhead);
(void) fprintf(stderr,
gettext("The last cluster is %d\n"), LastCluster);
}
}
/*
* XXX - right now we aren't attempting to fix anything that looks bad,
* instead we just give up.
*/
void
readBPB(int fd)
{
boot_sector_t ubpb;
/*
* The BPB is the first sector of the file system
*/
if (lseek64(fd, PartitionOffset, SEEK_SET) < 0) {
mountSanityCheckFails();
perror(gettext("Cannot seek to start of disk partition"));
(void) close(fd);
exit(7);
}
if (Verbose)
(void) fprintf(stderr,
gettext("Reading BIOS parameter block\n"));
if (read(fd, ubpb.buf, BPSEC) < BPSEC) {
mountSanityCheckFails();
perror(gettext("Read BIOS parameter block"));
(void) close(fd);
exit(2);
}
if (ltohs(ubpb.mb.signature) != BOOTSECSIG) {
mountSanityCheckFails();
(void) fprintf(stderr,
gettext("Bad signature on BPB. Giving up.\n"));
exit(2);
}
#ifdef _BIG_ENDIAN
swap_pack_grabbpb(&TheBIOSParameterBlock, &(ubpb.bs));
#else
(void) memcpy(&(TheBIOSParameterBlock.bpb), &(ubpb.bs.bs_front.bs_bpb),
sizeof (TheBIOSParameterBlock.bpb));
(void) memcpy(&(TheBIOSParameterBlock.ebpb), &(ubpb.bs.bs_ebpb),
sizeof (TheBIOSParameterBlock.ebpb));
#endif
/*
* In general, we would expect the bytes per sector to
* equal 256 (BPSEC). I personally have yet to see a file
* system where this isn't true but apparently some weird media
* have different sector sizes. So we'll accept a couple of
* other small multiples of 256 as valid sizes.
*/
if (TheBIOSParameterBlock.bpb.bytes_per_sector != BPSEC &&
TheBIOSParameterBlock.bpb.bytes_per_sector != 2 * BPSEC &&
TheBIOSParameterBlock.bpb.bytes_per_sector != 4 * BPSEC) {
mountSanityCheckFails();
(void) fprintf(stderr,
gettext("Bogus bytes per sector value. Giving up.\n"));
exit(2);
}
if (!(ISP2(TheBIOSParameterBlock.bpb.sectors_per_cluster) &&
IN_RANGE(TheBIOSParameterBlock.bpb.sectors_per_cluster,
1, 128))) {
mountSanityCheckFails();
(void) fprintf(stderr,
gettext("Bogus sectors per cluster value. Giving up.\n"));
(void) close(fd);
exit(6);
}
if (TheBIOSParameterBlock.bpb.sectors_per_fat == 0) {
#ifdef _BIG_ENDIAN
swap_pack_grab32bpb(&TheBIOSParameterBlock, &(ubpb.bs));
#else
(void) memcpy(&(TheBIOSParameterBlock.bpb32),
&(ubpb.bs32.bs_bpb32),
sizeof (TheBIOSParameterBlock.bpb32));
#endif
IsFAT32 = 1;
}
if (!IsFAT32) {
if ((TheBIOSParameterBlock.bpb.num_root_entries == 0) ||
((TheBIOSParameterBlock.bpb.num_root_entries *
sizeof (struct pcdir)) %
TheBIOSParameterBlock.bpb.bytes_per_sector) != 0) {
mountSanityCheckFails();
(void) fprintf(stderr,
gettext("Bogus number of root entries. "
"Giving up.\n"));
exit(2);
}
} else {
if (TheBIOSParameterBlock.bpb.num_root_entries != 0) {
mountSanityCheckFails();
(void) fprintf(stderr,
gettext("Bogus number of root entries. "
"Giving up.\n"));
exit(2);
}
}
/*
* In general, we would expect the number of FATs field to
* equal 2. Our mkfs and Windows have this as a default
* value. I suppose someone could override the default,
* though, so we'll sort of arbitrarily accept any number
* between 1 and 4 inclusive as reasonable values.
*
* XXX: Warn, but continue, if value is suspicious? (>2?)
*/
if (TheBIOSParameterBlock.bpb.num_fats > 4 ||
TheBIOSParameterBlock.bpb.num_fats < 1) {
mountSanityCheckFails();
(void) fprintf(stderr,
gettext("Bogus number of FATs. Giving up.\n"));
exit(2);
}
computeFileAreaSize();
}
|
